Hydrogels are hydrophilic, three-dimensional, and expandable matrices that are produced through chemical and/or physical crosslinking of certain polymers. In some cases, polysaccharide-based hydrogels have been prepared from a single polysaccharide such as carboxymethyl cellulose (CMC) and starch. CMC is an anionic water-soluble natural polymer derivative, which is widely used in detergents, oil exploration, and in the food, paper, and textile industries because of its viscosity-increasing properties. Starch is widely used in different fields such as food, environmental-friendly plastics, and medicine due to its low cost, biodegradability, and renewability. In this study, the polysaccharide hydrogels were prepared by esterification between hydroxyl groups of CMC and aldehyde group of modified starch. Epichlorohydrin and citric acid were used for crosslinker. The starches used in the experiments were corn starch, potato starch, and soluble starch. Sodium periodate was used as the oxidizing agent. The degree of aldehydes substitution (DS) of hydroxyl groups was varied with the amount of oxidizing agent, and the DS showed a minimum of 0.87 to a maximum of 2.79. As a result of analysis of the hydrogels, epichlorohydrin crosslinker showed a high swelling ratio when reacted with native starch. On the other hand, citric acid crosslinker showed good results when reacted with starch aldehydes. The maximum swelling ratio of hydrogel was about 50.

The PPS/MWCNTs/AlN composite was prepared with poly(phenylene sulfide) (PPS), covalent functionalized multi-walled carbon nanotubes (fMWCNTs), and aluminum nitride (AlN) via melt-blending techniques. The AlN is a non-oxidizing ceramic material having the highest thermal conductivity among the ceramic materials. A silane coupling agent was used to introduce the functional groups on the surface of the AIN, as it is able to graft with the functional groups on the covalent functionalized MWCNTs. The silanization reaction of the AlN was characterized qualitatively and quantitatively by FT-IR (Fourier Transform Infrared Spectroscopy), and XPS (X-ray Photoelectron Spectroscopy). The grafting reaction of the AlN particles on the MWCNTs was observed using UV–Vis (Ultraviolet-Visible Spectroscopy), FE-SEM (Field-Emission Scanning Electron Microscopy) and FE-TEM (Field-Emission Transmission Electron Microscopy) images. The grafting reaction was accomplished by observing the change of the transmittance, the morphology of the AlN particle bonded to the MWCNTs. For the morphological changes of the fractured surface of the PPS/MWCNTs/AlN composites by FE-SEM, the hybrid filler was homogeneously dispersed on the PPS matrix when the AlN particle was grafted on the MWCNTs. The homogeneous distribution of the hybrid filler acts as a heat transfer path, which led the improved thermal properties, such as thermal conductivity, thermal resistance, and melting temperature than those of not grafted MWCNTs.

We first report the construction of hybrid shish-kebab (HSK) superstructure in low-crystallinity elastomer nanocomposites with incorporation of Carbon Nanotube Bundles(CNTBs). With strong interfacial adhesion, the tensile strength of Olefin Block Copolymer(OBC)/CNTBs nanocomposites was tripled from 7.34MPa to 24.11MPa. With in-situ synchrotron small angle X-ray scattering(SAXS) and wide-angle X-ray diffraction(WAXD) as well as in-situ Raman spectra, the multi-scale structural evolution was thoroughly studied. The formation of HSK leads to lower lamellar density, exhibiting remarkably increased long period. Unlike that in neat OBC, the lower density of crystal lamellaes in nanocomposites doesn't dominate the evolution of long range orderness at low strain regions, the long period of nanocomposites exhibit an inversely increasing trend. With addition of CNTBs, the orientation behavior still follows the slip-link theory. With HSK acting as larger but fewer physical junctions, the chain connectivity of the soft and hard segments in OBC chains in nanocomposites is lower than that in neat OBC, it is less necessary for HSK to adjust their orientation status along the stretching direction. Thus the orientation factor of orthorhombic crystals at low strain regions is lower than that of neat OBC. The mesoscopic structural evolution of CNTBs can be directly revealed by the downshift trend of the Raman G’ band of CNTBs in nanocomposites, which reveals the axial deformation of CNTBs. The downshift can reach a maximum of 10.2 cm-1, and the downshift under axial deformation also conform to the slip-link theory and is consistent with the orientation status of HSK superstructure.

Probiotic microorganism’s consumption generates several benefits when they are significantly viable in the products in which they are applied. However, some processing conditions are unfavorable to their survival, as well as the food's own characteristics and storage conditions. Due to the low viability of probiotics when added as free cells, different technologies have been uses in order to increase their survival in food. Our study aimed to evaluate of Lactobacillus acidophilus encapsulation efficiency by the spray dryer using xantana pruni, which is produced by a Brasilian strain of Xanthomonas arboricola pv pruni, as encapsulating agent, and Aerosil ® as dispersant. Different encapsulating solutions were prepared in according to a rotational central composite design (RCCD) (p < 0.05), using a full factorial 22 with triplicate at the central point, totaling 11 treatments. Glycerol was added at 20% relative to the total polymer mass. The microcapsules were produced in spray dryer (LabMaq MSD 1.0), with inlet temperature of 120 °C and outlet of 60 °C, with an air flow rate of 3 L.h-1 and inlet speed of 0.4 L.h-1. The microcapsules were stored in a desiccator at 25 °C. The survival percents were determined by comparing the concentration of viable microorganisms after the dryer process with the initial microbial concentrations. Xanthan pruni exerted positive effect on the microorganism viability within the studied range (r = 0.9423). The mathematical model generated (viability (%) = 75.10 + 1.90X2 - 1.62A) was predictive and significant within the studied range (r = 0.667). A positive influence of the concentration of xanthan pruni in the microbial viability after dryer process was observed; which was caused, probably, by thermal protection due to the microorganisms encapsulation. These results denote xanthan pruni as potential encapsulating agent to probiotics microorganisms.

Poly(3-hydroxybutyrate) [P(3HB)] is a biodegradable biopolymer accumulated by some microorganisms as inclusions of polyesters. The cost of production to the P(3HB) can be lower by increasing cellular and polymer concentrations by suitable combinations of nutrients in the culture medium and cheaper raw materials as media components. The purpose of this study was to evaluate the effect of three minerals media with different nitrogen sources (F4 - urea, BEI - yeast extract and MM - ammonium sulfate) and carbon sources (glucose, sucrose) in the P(3HB) production whit Ralstonia solanacearum RS bacterium. The bioprocesses occured in 250 mL Erlenmeyer flasks with 80 mL of mineral medium, containing 40 g.L-1 of carbon source, and 20 mL of inoculum. The incubations occurred at 32 °C with shaking at 250 rpm for 24, 48 and 72 h. Cell growth was evaluated by optical density (OD600nm) and by dry cell weight (DCW) concentration. The DCW and P(3HB) production was determined by gravimetry. P(3HB) recuperation was performed by chemical extraction using chloroform and DCW in the ratio of 40:1 v.m-1. Residual sugars from the cultures was determined by the dinitrosalicylic acid method for reducer sugars. The best results to DCW (5.3 g.L-1) and accumulation of P(3HB) (46.8% or 2.66 g.L-1) were obtained using MM medium with sucrose in 72 h. For the OD600nm, there was no significant difference between 48 and 72 h in MM medium with sucrose or glucose. All cultures presented similar pattern of sugar consumption, with greater variation of the concentration available in the medium in the first 24 h. The lower sugar consumption occurred in F4 medium, which justify the low yields of DCW and OD600nm in this medium. The selected medium for future research is the MM with sucrose, as it presented better results in the analyzes performed.